1. Field of the Invention
The invention is related to the field of communications and, in particular, to authentication loading control and information recapture in UMTS networks.
2. Statement of the Problem
Universal Mobile Telecommunications System, or UMTS, is a third-generation (3G) wireless communication technology that offers broadband, packet-based multimedia and data services to users having suitably equipped user equipment (UE) comprising, for example, cell phones, mobile computers or the like. For a UMTS call, an originating or terminating UE wirelessly communicates, via RF resources, with a radio access network known as a UTRAN (UMTS Terrestrial Radio Access Network). A UMTS core network connects the UTRAN to an external packet network (e.g., the Internet). The UMTS core network provides mobility management, session management and transport for Internet Protocol packet services including, for example, high speed data, music and video downloads and live TV. The UMTS core network also provides support for additional functions, including, without limitation, authentication, charging and lawful interception (a.k.a., wiretapping).
A Serving GPRS (General Packet Radio Services) Support Node (SGSN) is the element of the UMTS core network that is responsible for authentication, session management, packet routing and mobility management. The SGSN also supports charging and lawful intercept functions in concert with respective charging and lawful intercept gateway elements of the core network. Conventionally, the SGSN performs an authentication procedure whenever a UE attaches to the network, to confirm that the UE is a valid user of the network services requested. As a part of the authentication procedure, the SGSN obtains an International Mobile Equipment Identity (IMEI) number uniquely associated with the UE. Alternatively or additionally, the SGSN may obtain an IMEI-SV, an encrypted form of IMEI from which IMEI can be derived. In either case, the IMEI is used to identify the UE for purposes of authentication, charging and lawful intercept functions.
A problem that arises, most particularly during periods of high demand on network resources, is that the service provider may desire a more flexible arrangement for performing authentication procedures. For example, the service provider may wish to perform authentication procedures less frequently in high volume situations to reduce SGSN loading and enhance system performance. However, if authentication is performed less frequently, there will be instances when the IMEI is not obtained for one or more UEs coincident to authentication, yet the SGSN relies on the IMEI to support functions including, without limitation, charging and lawful intercept functions.